P.E. de Felício

CARACTERÍSTICAS DE QUALIDADE DO CONTRAFILÉ (m. L. dorsi) DE TOUROS JOVENS DA RAÇA NELORE

Quality traits of boneless rib cut (L. dorsi muscle) from Nelore young bulls. To study the meat quality traits of Nelore breed young bulls, and the effect of age (690-780 days) on them, 113 animals were slaughtered after 109 days of intensive feeding with 20% concentrate and 80% roughage. All the carcasses were graded at the slaughter floor by the Federal Inspection and chilled for 24 hours (Tinitial=5°C, Tfinal=2°C). Fifty one half carcasses (right side), type B - B R A S I L `s grading system - from animals of 23 to 26 months were boned and separated into commercial cuts. Two steaks (2.5cm thick) were removed from each boneless rib cut (m. L. dorsi), vacuum packaged and aged for 7 days (0-2°C). The pH varied from 5.44 to 5.83 and only two samples had pH ³ 5.70. The L* (brightness) average value was 34.85. The water and fat content were 75.65% and 1.71%, respectively. The average WB shear force was 6.70kg, and it was not affected by age (690-734 days), but presented a trend (t test, p=0.22) for increasing values between 735 and 780 days. Animal age did not affect other quality traits (t test, p>0.20). It was concluded that the rib cut from Nelore young bulls may not have a good acceptability in exigent markets, and that carcasses graded B, presumed to be the best grade, do not necessarily present the best meat quality characteristics.

Effects of teeth maturity and fatness of Nellore (Bos indicus) steer carcasses on instrumental and sensory tenderness

This study sought to evaluate the effects of teeth maturity and carcass fatness on physical and sensory traits of the beef ribeye (M. longissimus thoracis). Carcass sides (n=60) of Nellore steers were grouped into six categories, according to teeth maturity (2, 4 and 6 permanent incisors), and fatness (2 - slight and 3 - average). The boneless ribeye cuts (6th - 9th ribs) were vacuum packed and aged for 14days. Steaks, 2.5cm thick, were evaluated as to sarcomere length, shear force and sensory attributes. Sarcomere length was not affected (P>0.05) by maturity or fatness. Teeth maturity did not influence (P>0.05) tenderness measured by instrumental or sensory analysis, however rib steaks from fatter carcasses displayed better tenderness (P<0.01) and lower cooking losses (P<0.01). In the Nellore steer carcasses produced in Brazil, fatness may be more important than teeth maturity to improve meat tenderness.

Effects of chilling rate and spray-chilling on weight loss and tenderness in beef strip loin steaks

We evaluated the effects of chilling rate and the use of a spray-chilling system on the weight loss by evaporation on carcasses. We also evaluated the effects on meat purge in vacuum package, cooking losses, and on parameters related to the tenderness of strip loin steaks (M. longissimus lumborum). Forty non-castrated males of approximately 12 months old, finished in feed-lot were harvested in 16 Montana cattle (a composite breed), and 24 SimmentalxNellore crossbred cattle. After bleeding, the bodies were electrically stimulated and assigned to one of the four treatments: conventional air-chilling (CAC), conventional spray-chilling (CSC), slow air-chilling (SAC), and slow spray-chilling (SSC). Strip loin steaks (M. longissimus lumborum) of approximately 2.5 cm thick were removed, vacuum packed and aged for 7, 14, 30 or 60 days. Samples were analyzed for sarcomere length, myofibrillar fragmentation index, Warner-Bratzler shear force, and weight losses by purge and cooking. Spraying was efficient in reducing weight loss by evaporation (P<0.05). Effects of treatments and aging period on purge losses were observed, where samples from sprayed carcasses or aged cuts showed higher losses. Cooking losses were not affected either by spraying or aging. The slow chilling, with or without spraying, was more efficient in producing strip loin steaks with lower average shear force and longer sarcomere. The myofibrillar fragmentation index increased with aging time, but was not affected by carcasses spraying.

Effects of breed and nutrition on the productive traits of Zebu, Charolais and crossbreed beef cattle in south-east Brazil— Part 1: Body and gross carcase composition

A study of the effects of breed and nutrition on the productive traits of Nelore, Guzerá, Charolais and Canchim cattle found in south-east Brazil was undertaken as part of an overall research programme to differentiate between carcase classes with a view to elaborating carcase classification proposals. The forty animals used in this study were divided into two treatment groups representing intensive and extensive feeding systems. Recovered data were analysed to determine the effects of breed, treatment and possible breed-treatment interaction on the proportions of internal and external offals and gross carcase composition. The results demonstrated that although some differences in carcase composition could be attributed to breed effect, most were caused by the varying nutrional status of the animals pre-slaughter. The Charolais-and, to a lesser extent, the Canchim animals-were seriously maladjusted to the harsh range conditions and showed lower daily liveweight gains and reduced liveweight at slaughter. The significantly lower special hindquarters and higher forequarter proportions in the Zebu animals were thought to be due to the cervical enlargement of the rhomboid muscle and earlier sexual maturity in the Bos indicus animals.

Effects of breed and nutrition on the productive traits of beef cattle in South East Brazil: Part 2—Tissue distribution and carcase composition

This paper is the second in a series recording the effects of breed and nutrition on the productive traits of Nelore, Guzerá, Charolais and Canchim cattle in south-east Brazil. Significant treatment variations were recorded in carcase bone weights but differences in meat to bone ratios were not sufficiently marked to demonstrate that bone might grow at the expense of muscle when animals are maintained on particularly severe nutritional regimes. A simple carcase weight to length ratio was shown to be highly correlated with total bone proportion but not with yield of saleable meat. Recovery of total saleable meat was only marginally and not significantly affected by breed but was significantly affected by treatment. The increased levels of fatness in the carcases of the zebu and, in particular, all animals finished in feedlot, that affected the yield of saleable meat, was also thought to be responsible for the decreased recovery of first quality meat in these carcases. In general, tissue differences were more noticeable between treatments than between breeds and reflected the varying nutritional status of the animals pre-slaughter.

α- and γ-tocopherol levels in Nelore steer blood plasma after a single oral treatment of soybean oil deodorizer distillate (SODD)

The paper presents a study on the effect of a treatment of steers with a single oral dose of soybean oil deodorizer distillate (SODD) on the α- and γ-tocopherol blood plasma concentrations. SODD containing 1.95% of α-tocopherol and 8.45% of γ-tocopherol in doses of 0.75, 1.50 or 2.25g/kg live weight was used on nine 2-year-old Nelore (Bos indicus) steers to promote increases in the plasma concentration of vitamin E. Tocopherol analyses were performed by HPLC on a C18 column, using a UV detector. The results showed that a single oral treatment of steers with SODD produces significant increases in plasma α- and γ-tocopherol levels. The vitamin E content was increased up to four times the initial content, showing the high capacity of SODD as a source of vitamin E for bovines in a single oral dose with the objective of increasing vitamin E blood plasma concentrations and, consequently, the levels in the tissues, as well.